The flexor pollicis longus is a muscle within the deep compartment of the anterior forearm.
- Attachments: Originates from the anterior surface of the radius and surrounding interosseous membrane. The tendon passes through the carpal tunnel and attaches to the base of the distal phalanx of the thumb.
- Actions: Flexes the interphalangeal joint and metacarpophalangeal joint of the thumb.
- Innervation: Median nerve (anterior interosseous branch).
- Blood supply: Ulnar artery